Their daughter's girlfriend, identified only as Hang, called her last December and promised to pay VND20 million (nearly US$1,000) for each girl she sent over.

Hoa was arrested while trying to bring her first victim, Cut Thi Rau, through the Mong Cai border gate in Quang Ninh Province on the night of December 12.

Her two alleged accomplices, Cut Thi May and Mong Thi Nga, also Nghe An locals, are still at large.

May allegedly produced Nga, but decided not to traffic her after Hoa determined she was too ugly. Nga then found Rau and told her a false story about a good job waiting for her at a company in China.

Vi Thi Hoa, 50, and her husband La Van Phanh, 55, stand at a trial in Nghe An Province on June 17 for attempting to traffic a local woman to China for $1,000. Photo credit: Dan Tri

Police arrested Nguyen Ngoc Lan of the Nghe An Legal Assistance Center last May, after charging him with taking bribes from Hoa’s family to help her avoid sentencing.

The family turned Lan in, saying he had accepted VND100 million ($4,730) from them in late 2013 and refused to return the money after telling them he could do nothing to help Hoa.

The family accused Lan of promising to either help get Hoa off with a suspended sentence or make sure she went free after the trial.

Figures released in 2013 showed that Vietnamese police have busted more than 3,000 human-trafficking attempts along the Chinese border since 2003.

Authorities rescued around 1,200 would-be victims in 2012, alone.

Many were bound for brothels or Chinese men willing to pay for wives.

In late 2013, Chinese news agency Xinhua quoted Sun Xiaoying, a researcher with the Research Institute of Southeast Asia at the Guangxi Academy of Social Sciences, as saying that China’s gender imbalance had led to a surge in demand for Vietnamese wives.

China had 697.2 million males and 663.4 million females in 2013, which meant that there were 33.8 million more men than women, according to statistics published by China's National Bureau of Statistic in January this year.